/*
 * qca_securemessage.h - Qt Cryptographic Architecture
 * Copyright (C) 2003-2005  Justin Karneges <justin@affinix.com>
 * Copyright (C) 2004,2005  Brad Hards <bradh@frogmouth.net>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 *
 */

/**
   \file qca_securemessage.h

   Header file for secure message (PGP, CMS) classes

   \note You should not use this header directly from an
   application. You should just use <tt> \#include \<QtCrypto>
   </tt> instead.
*/

#ifndef QCA_SECUREMESSAGE_H
#define QCA_SECUREMESSAGE_H

#include <QObject>
#include "qca_core.h"
#include "qca_publickey.h"
#include "qca_cert.h"

class QDateTime;

namespace QCA
{
	class SecureMessageSystem;

	/**
	   \class SecureMessageKey qca_securemessage.h QtCrypto

	   Key for SecureMessage system
	*/
	class QCA_EXPORT SecureMessageKey
	{
	public:
		/**
		   The key type
		*/
		enum Type
		{
			None, ///< no key
			PGP,  ///< Pretty Good Privacy key
			X509  ///< X.509 CMS key
		};

		/**
		   Construct an empty key
		*/
		SecureMessageKey();

		/**
		   Standard copy constructor

		   \param from the source key
		*/
		SecureMessageKey(const SecureMessageKey &from);

		~SecureMessageKey();

		/**
		   Standard assignment operator

		   \param from the source key
		*/
		SecureMessageKey & operator=(const SecureMessageKey &from);

		/**
		   Returns true for null object
		*/
		bool isNull() const;

		/**
		   The key type
		*/
		Type type() const;

		// pgp
		/**
		   Public key part of a PGP key
		*/
		PGPKey pgpPublicKey() const;

		/**
		   Private key part of a PGP key
		*/
		PGPKey pgpSecretKey() const;

		/**
		   Set the public key part of a PGP key

		   \param pub the PGP public key
		*/
		void setPGPPublicKey(const PGPKey &pub);

		/**
		   Set the private key part of a PGP key

		   \param sec the PGP secretkey
		*/
		void setPGPSecretKey(const PGPKey &sec);

		// x509
		/**
		   The X.509 certificate chain (public part) for this key
		*/
		CertificateChain x509CertificateChain() const;

		/**
		   The X.509 private key part of this key
		*/
		PrivateKey x509PrivateKey() const;

		/**
		   Set the public key part of this X.509 key.
		*/
		void setX509CertificateChain(const CertificateChain &c);

		/**
		   Set the private key part of this X.509 key.
		*/
		void setX509PrivateKey(const PrivateKey &k);

		// generic
		/**
		   Test if this key contains a private key part
		*/
		bool havePrivate() const;

		/**
		   The name associated with this key

		   For a PGP key, this is the primary user ID

		   For an X.509 key, this is the Common Name
		*/
		QString name() const;

	private:
		class Private;
		QSharedDataPointer<Private> d;
	};

	/**
	   A list of message keys
	*/
	typedef QList<SecureMessageKey> SecureMessageKeyList;

	/**
	   \class SecureMessageSignature qca_securemessage.h QtCrypto

	   SecureMessage signature
	*/
	class QCA_EXPORT SecureMessageSignature
	{
	public:
		/**
		   The result of identity verification
		*/
		enum IdentityResult
		{
			Valid,            ///< indentity is verified, matches signature
			InvalidSignature, ///< valid key provided, but signature failed
			InvalidKey,       ///< invalid key provided
			NoKey             ///< identity unknown
		};

		/**
		   Create an empty signature check object
		*/
		SecureMessageSignature();

		/**
		   Create a signature check object
		*/
		SecureMessageSignature(IdentityResult r, Validity v, const SecureMessageKey &key, const QDateTime &ts);

		/**
		   Standard copy constructor

		   \param from the source signature object
		*/
		SecureMessageSignature(const SecureMessageSignature &from);

		~SecureMessageSignature();

		/**
		   Standard assignment operator

		   \param from the source signature object
		*/
		SecureMessageSignature & operator=(const SecureMessageSignature &from);

		/**
		   get the results of the identity check on this signature
		*/
		IdentityResult identityResult() const;

		/**
		   get the results of the key validation check on this signature
		*/
		Validity keyValidity() const;

		/**
		   get the key associated with this signature
		*/
		SecureMessageKey key() const;

		/**
		   get the timestamp associated with this signature
		*/
		QDateTime timestamp() const;

	private:
		class Private;
		QSharedDataPointer<Private> d;
	};

	/**
	   A list of signatures
	*/
	typedef QList<SecureMessageSignature> SecureMessageSignatureList;

	/**
	   \class SecureMessage qca_securemessage.h QtCrypto

	   Class representing a secure message

	   SecureMessage presents a unified interface for working with both
	   OpenPGP and CMS (S/MIME) messages.  Prepare the object by calling
	   setFormat(), setRecipient(), and setSigner() as necessary, and then
	   begin the operation by calling an appropriate 'start' function, such
	   as startSign().

	   Here is an example of how to perform a Clearsign operation using PGP:

	   \code
// first make the SecureMessageKey
PGPKey myPGPKey = getSecretKeyFromSomewhere();
SecureMessageKey key;
key.setPGPSecretKey(myPGPKey);

// our data to sign
QByteArray plain = "Hello, world";

// let's do it
OpenPGP pgp;
SecureMessage msg(&pgp);
msg.setSigner(key);
msg.startSign(SecureMessage::Clearsign);
msg.update(plain);
msg.end();
msg.waitForFinished(-1);

if(msg.success())
{
	QByteArray result = msg.read();
	// result now contains the clearsign text data
}
else
{
	// error
	...
}
	   \endcode

	   Performing a CMS sign operation is similar.  Simply set up the SecureMessageKey
	   with a Certificate instead of a PGPKey, and operate on a CMS object instead of
	   an OpenPGP object.

	   \sa SecureMessageKey
	   \sa SecureMessageSignature
	   \sa OpenPGP
	   \sa CMS
	*/
	class QCA_EXPORT SecureMessage : public QObject, public Algorithm
	{
		Q_OBJECT
	public:
		/**
		   The type of secure message
		*/
		enum Type
		{
			OpenPGP, ///< a Pretty Good Privacy message
			CMS      ///< a Cryptographic Message Syntax message
		};

		/**
		   The type of message signature
		*/
		enum SignMode
		{
			Message,    ///< the message includes the signature
			Clearsign,  ///< the message is clear signed
			Detached    ///< the signature is detached
		};

		/**
		   Formats for secure messages
		*/
		enum Format
		{
			Binary, ///< DER/binary
			Ascii   ///< PEM/ascii-armored
		};

		/**
		   Errors for secure messages
		*/
		enum Error
		{
			ErrorPassphrase,       ///< passphrase was either wrong or not provided
			ErrorFormat,           ///< input format was bad
			ErrorSignerExpired,    ///< signing key is expired
			ErrorSignerInvalid,    ///< signing key is invalid in some way
			ErrorEncryptExpired,   ///< encrypting key is expired
			ErrorEncryptUntrusted, ///< encrypting key is untrusted
			ErrorEncryptInvalid,   ///< encrypting key is invalid in some way
			ErrorNeedCard,         ///< pgp card is missing
			ErrorCertKeyMismatch,  ///< certificate and private key don't match
			ErrorUnknown           ///< other error
		};

		/**
		   Create a new secure message

		   This constructor uses an existing
		   SecureMessageSystem object (for example, an OpenPGP
		   or CMS object) to generate a specific kind of
		   secure message.

		   \param system a pre-existing and configured SecureMessageSystem object
		*/
		SecureMessage(SecureMessageSystem *system);
		~SecureMessage();

		/**
		   The Type of secure message
		*/
		Type type() const;

		/**
		   Test if the message type supports multiple
		   (parallel) signatures.

		   \return true if the secure message support multiple
		   parallel signatures

		   \note PGP cannot do this - it is primarily a CMS
		   feature
		*/
		bool canSignMultiple() const;

		/**
		   True if the SecureMessageSystem can clearsign
		   messages.

		   \note CMS cannot clearsign - this is normally only
		   available for PGP
		*/
		bool canClearsign() const;

		/**
		   True if the SecureMessageSystem can both sign and
		   encrypt (in the same operation).

		   \note CMS cannot do an integrated sign/encrypt -
		   this is normally only available for PGP. You can do
		   separate signing and encrypting operations on the
		   same message with CMS though.
		*/
		bool canSignAndEncrypt() const;

		/**
		   Reset the object state to that of original construction.
		   Now a new operation can be performed immediately.
		*/
		void reset();

		/**
		   For CMS only, this will bundle the signer certificate chain
		   into the message.  This allows a message to be verified
		   on its own, without the need to have obtained the signer's
		   certificate in advance.  Email clients using S/MIME often
		   bundle the signer, greatly simplifying key management.

		   This behavior is enabled by default.
		*/
		void setEnableBundleSigner(bool b);

		/**
		   For CMS only, this will put extra attributes into the
		   message related to S/MIME, such as the preferred
		   type of algorithm to use in replies.  The attributes
		   used are decided by the provider.

		   This behavior is enabled by default.
		*/
		void setEnableSMIMEAttributes(bool b);

		/**
		   Set the Format used for messages

		   The default is Binary.

		   \param f whether to use Binary or Ascii
		*/
		void setFormat(Format f);

		/**
		   Set the recipient for an encrypted message

		   \sa setRecipients
		*/
		void setRecipient(const SecureMessageKey &key);

		/**
		   Set the list of recipients for an encrypted message.

		   For a list with one item, this has the same effect as setRecipient.

		   \sa setRecipient
		*/
		void setRecipients(const SecureMessageKeyList &keys);

		/**
		   Set the signer for a signed message.

		   This is used for both creating signed messages as well as for
		   verifying CMS messages that have no signer bundled.

		   \sa setSigners
		*/
		void setSigner(const SecureMessageKey &key);

		/**
		   Set the list of signers for a signed message.

		   This is used for both creating signed messages as well as for
		   verifying CMS messages that have no signer bundled.

		   For a list with one item, this has the same effect as setSigner.

		   \sa setSigner
		*/
		void setSigners(const SecureMessageKeyList &keys);

		/**
		   Start an encryption operation

		   You will normally use this with some code along
		   these lines:
		   \code
		   encryptingObj.startEncrypt();
		   encryptingObj.update(message);
		   // perhaps some more update()s
		   encryptingObj.end();
		   \endcode

		   Each update() may (or may not) result in some
		   encrypted data, as indicated by the readyRead()
		   signal being emitted. Alternatively, you can wait
		   until the whole message is available (using either
		   waitForFinished(), or use the finished()
		   signal. The encrypted message can then be read
		   using the read() method.
		*/
		void startEncrypt();

		/**
		   Start an decryption operation

		   You will normally use this with some code along
		   these lines:
		   \code
		   decryptingObj.startEncrypt();
		   decryptingObj.update(message);
		   // perhaps some more update()s
		   decryptingObj.end();
		   \endcode

		   Each update() may (or may not) result in some
		   decrypted data, as indicated by the readyRead()
		   signal being emitted. Alternatively, you can wait
		   until the whole message is available (using either
		   waitForFinished(), or the finished()
		   signal). The decrypted message can then be read
		   using the read() method.

		   \note If decrypted result is also signed (not for
		   CMS), then the signature will be verified during
		   this operation.
		*/
		void startDecrypt();

		/**
		   Start a signing operation

		   You will normally use this with some code along
		   these lines:
		   \code
		   signingObj.startSign(QCA::SecureMessage::Detached)
		   signingObj.update(message);
		   // perhaps some more update()s
		   signingObj.end();
		   \endcode

		   For Detached signatures, you won't get any results
		   until the whole process is done - you either
		   waitForFinished(), or use the finished() signal, to
		   figure out when you can get the signature (using
		   the signature() method, not using read()). For
		   other formats, you can use the readyRead() signal
		   to determine when there may be part of a signed
		   message to read().

		   \param m the mode that will be used to generate the
		   signature
		*/
		void startSign(SignMode m = Message);

		/**
		   Start a verification operation

		   \param detachedSig the detached signature to
		   verify. Do not pass a signature for other signature
		   types.
		*/
		void startVerify(const QByteArray &detachedSig = QByteArray());

		/**
		   Start a combined signing and encrypting
		   operation. You use this in the same way as
		   startEncrypt().

		   \note This may not be possible (e.g. CMS
		   cannot do this) - see canSignAndEncrypt() for a
		   suitable test.
		*/
		void startSignAndEncrypt();

		/**
		   Process a message (or the next part of a message)
		   in the current operation. You need to have already
		   set up the message (startEncrypt(), startDecrypt(),
		   startSign(), startSignAndEncrypt() and
		   startVerify()) before calling this method.

		   \param in the data to process
		*/
		void update(const QByteArray &in);

		/**
		   Read the available data.

		   \note For detached signatures, you don't get
		   anything back using this method. Use signature() to
		   get the detached signature().
		*/
		QByteArray read();

		/**
		   The number of bytes available to be read.
		*/
		int bytesAvailable() const;

		/**
		   Complete an operation.

		   You need to call this method after you have
		   processed the message (which you pass in as the
		   argument to update().

		   \note the results of the operation are not
		   available as soon as this method returns. You need
		   to wait for the finished() signal, or use
		   waitForFinished().
		*/
		void end();

		/**
		   Block until the operation (encryption, decryption,
		   signing or verifying) completes.

		   \param msecs the number of milliseconds to wait for
		   the operation to complete. Pass -1 to wait
		   indefinitely.

		   \note You should not use this in GUI
		   applications where the blocking behaviour looks
		   like a hung application. Instead, connect the
		   finished() signal to a slot that handles the
		   results.
		*/
		bool waitForFinished(int msecs = 30000);

		/**
		   Indicates whether or not the operation was successful
		   or failed.  If this function returns false, then
		   the reason for failure can be obtained with errorCode().

		   \sa errorCode
		   \sa diagnosticText
		*/
		bool success() const;

		/**
		   Returns the failure code.

		   \sa success
		   \sa diagnosticText
		*/
		Error errorCode() const;

		/**
		   The signature for the message. This is only used
		   for Detached signatures. For other message types,
		   you get the message and signature together using
		   read().
		*/
		QByteArray signature() const;

		/**
		   The name of the hash used for the signature process
		*/
		QString hashName() const;

		// verify
		/**
		   Test if the message was signed.

		   This is true for OpenPGP if the decrypted message
		   was also signed.

		   \return true if the message was signed.
		*/
		bool wasSigned() const;

		/**
		   Verify that the message signature is correct.

		   \return true if the signature is valid for the
		   message, otherwise return false
		*/
		bool verifySuccess() const;

		/**
		   Information on the signer for the message
		*/
		SecureMessageSignature signer() const;

		/**
		   Information on the signers for the message. 

		   This is only meaningful if the message type supports
		   multiple signatures (see canSignMultiple() for a
		   suitable test).
		*/
		SecureMessageSignatureList signers() const;

		/**
		   Returns a log of technical information about the operation,
		   which may be useful for presenting to the user in an
		   advanced error dialog.
		*/
		QString diagnosticText() const;

	Q_SIGNALS:
		/**
		   This signal is emitted when there is some data to
		   read. Typically you connect this signal to a slot
		   that does a read() of the available data.

		   \note This signal does not mean that the processing
		   of a message is necessarily complete - see
		   finished().
		*/
		void readyRead();

		/**
		   This signal is emitted when the message is fully
		   processed.
		*/ 
		void finished();

	private:
		class Private;
		friend class Private;
		Private *d;
	};

	/**
	   \class SecureMessageSystem qca_securemessage.h QtCrypto

	   Abstract superclass for secure messaging systems

	   \sa SecureMessage
	   \sa SecureMessageKey
	*/
	class QCA_EXPORT SecureMessageSystem : public QObject, public Algorithm
	{
		Q_OBJECT
	public:
		~SecureMessageSystem();

	protected:
		/**
		   Protected constructor for SecureMessageSystem
		   classes. You are meant to be using a subclass (such
		   as OpenPGP or CMS) - you only need to worry about
		   this class if you are creating a whole new
		   SecureMessageSystem type.

		   \param parent the parent object for this object
		   \param type the name of the Type of
		   SecureMessageSystem to create
		   \param provider the provider to use, if a specific
		   provider is required.
		*/
		SecureMessageSystem(QObject *parent, const QString &type, const QString &provider);
	};

	/**
	   \class OpenPGP qca_securemessage.h QtCrypto

	   Pretty Good Privacy messaging system

	   \sa SecureMessage
	   \sa SecureMessageKey
	*/
	class QCA_EXPORT OpenPGP : public SecureMessageSystem
	{
		Q_OBJECT
	public:
		/**
		   Standard constructor

		   \param parent the parent object for this object
		   \param provider the provider to use, if a specific
		   provider is required
		*/
		OpenPGP(QObject *parent = 0, const QString &provider = QString());
		~OpenPGP();
	};

	/**
	   \class CMS qca_securemessage.h QtCrypto

	   Cryptographic Message Syntax messaging system

	   Cryptographic Message Syntax (%CMS) "is used to digitally
	   sign, digest, authenticate, or encrypt arbitrary message
	   content.  The %CMS describes an encapsulation syntax for
	   data protection.  It supports digital signatures and
	   encryption.  The syntax allows multiple encapsulations; one
	   encapsulation envelope can be nested inside another.
	   Likewise, one party can digitally sign some previously
	   encapsulated data.  It also allows arbitrary attributes,
	   such as signing time, to be signed along with the message
	   content, and provides for other attributes such as
	   countersignatures to be associated with a signature." (from
	   <a href="http://www.ietf.org/rfc/rfc3852.txt">RFC3852</a>
	   "Cryptographic Message Syntax")

	   \sa SecureMessage
	   \sa SecureMessageKey
	*/
	class QCA_EXPORT CMS : public SecureMessageSystem
	{
		Q_OBJECT
	public:
		/**
		   Standard constructor

		   \param parent the parent object for this object
		   \param provider the provider to use, if a specific
		   provider is required
		*/
		CMS(QObject *parent = 0, const QString &provider = QString());
		~CMS();

		/**
		   Set the trusted certificates to use for the
		   messages built using this CMS object.

		   \param trusted the collection of trusted
		   certificates to use
		*/
		void setTrustedCertificates(const CertificateCollection &trusted);

		/**
		   Set the private keys to use for the messages built
		   using this CMS object.

		   Keys are required for decrypting and signing (not
		   for encrypting or verifying).

		   \param keys the collection of keys to use
		*/
		void setPrivateKeys(const SecureMessageKeyList &keys);
	};
}

#endif
